


A New Line of Thought

by General_Button



Category: Sherlock (TV), Sherlock Holmes & Related Fandoms
Genre: Bottom!Sherlock, Consensual, M/M, PWP, Sherlock Has Tentacles, Tentacle Sex, Tentacles, Unsafe Sex, in many ways
Language: English
Status: Completed
Published: 2015-11-07
Updated: 2015-11-07
Packaged: 2018-04-30 12:16:19
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 6,651
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5163515
Author URL: https://archiveofourown.org/users/General_Button/pseuds/General_Button
Summary: <blockquote class="userstuff">
              <p>What greeted him was something straight out of a film. A sharp, crawling sensation ran down John’s spine. For one horrifying moment, he worried he’d wet himself.</p><p>It was Sherlock. He was sitting on his bed, and he was…parts of him were…<i>moving</i>. Wild, elongated <i>things</i> were coming out his back. Most of them were long and fairly thin, although one or two were as fat as his forearm. They writhed around his body, pressing against his skin before spreading. Sherlock groaned again; a dark, guttural sound of pure satisfaction. John took a step back, and then another.</p><p>John felt deprived of oxygen, faint with skin-crawling horror. <i>My flatmate is some kind of monster, </i>he thought wildly.</p>
            </blockquote>





	A New Line of Thought

**Author's Note:**

> Trying to get back back into doing the stuff I love by writing dirty, kinky tentacle sex. Unbeta'd so please excuse any little mistakes I may have missed.

“Sherlock?”

John shut the door behind him and dropped his bag to the floor. The flat was silent save for the humming of the fish tank that sat in the middle of their living room. Sherlock hadn’t specified why, exactly, he needed an empty tank filled with water, but John’s questions had been met with stony silence. As he observed the glass behemoth, John mused that must have been hell to lift that up their stairwell.

“Sherlock, are you home?” he called, listlessly, expecting no answer. Either he was in his usual meditative state of thinking, or he was out for one reason or another. John didn’t mind; having the flat to himself would be a welcome change.

John set out the kettle and filled it with water before returning to the living room. He grabbed the remote, and just as he went to turn on the screen, he heard a muted groan. John froze and waited. Not a sound echoed for a full minute, and then: again, another groan.

It sounded like Sherlock.

John set down the remote and crept down the hallway, something urging him to be quiet. “Sherlock?” he whispered. The sounds came louder now, and they were originating from Sherlock’s room. He stepped closer, wary. Was Sherlock in trouble or…?

A slick sound emanated and for a very embarrassing moment John thought Sherlock was using a sex toy, but no; it sounded different. It was something else. The door was open, so John poked it with his finger.

What greeted him was something straight out of a film. A sharp, crawling sensation ran down John’s spine. For one horrifying moment, he worried he’d wet himself.

It was Sherlock. He was sitting on his bed, and he was…parts of him were… _moving_. Wild, elongated _things_ were coming out his back. Most of them were long and fairly thin, although one or two were as fat as his forearm. They writhed around his body, pressing against his skin before spreading. Sherlock groaned again; a dark, guttural sound of pure satisfaction. John took a step back, and then another.

John felt deprived of oxygen, faint with skin-crawling horror. His head was swimming with horror as well as sharp relief—Sherlock hadn’t heard him.

 _My flatmate is some kind of monster_ , he thought. _That, or something else has taken his place._

As he observed, unable to look away from the sight, the things running along Sherlock’s back began to move with more purpose. The tips of the fleshy, pink bodies stroked and caressed his body. John couldn’t see Sherlock’s face, but from the sound of his voice and the way the tentacles began nudging at his arse, he was enjoying some fucked up form of self-pleasure. One of them wrapped around his throat and pinched at the skin just underneath his jaw until it left a vivid mark.

“Oh god,” he whispered. “Oh my god.”

Maybe the second most horrifying bit of it all was that John was hard.

Numb, he turned and got out of there as quickly and quietly as possible. The steps on the stairs leading out of the flat creaked below his feet, but he was too far gone to care.

Once outside in the open air, John took a left and went into _Speedy’s_ , where he spent an hour nursing a sandwich and tea, trying to convince himself what he’d seen was an illusion. _Sherlock drugged me. I couldn’t have seen…what I saw_.

Even once he had nothing left on his plate but crumbs and the other occupants were giving him curious looks, he couldn’t stomach the thought of going back to the flat just yet. John stood up, nodded absently to a woman that was eyeing him, and left to take a walk around London.

He wandered aimlessly for another good few hours, trying to think of anything but what he’d seen (and failing) until his leg ached so fiercely that he had to sit down and massage the kinks out of it.

When he went back (and he would, there was no doubt) Sherlock would probably want to know why he was in such a state, probably, but that wasn’t his concern.

_My best friend is something out of a bad horror film, and somehow, despite all that, I was aroused._

Eventually, lacking any other means with which to occupy himself, John had no choice but to return to Baker Street.

When he wearily trudged up the stairs and walked into the doorway, Sherlock was sitting on the sofa, looking for all intents and purposes abysmally bored.

“John,” Sherlock greeted, dragging out the syllable. “You came home hours ago, started to watch one of your ridiculous shows, and then left. Where have you been?”

If he didn’t know any better, he’d say Sherlock sounded nervous. His eyes darted towards his room, and John forced himself not to let his gaze wander there.

“Got,” he cleared his throat. “Got a call. Sarah. She, uh, needed help with something and you weren’t home, so I just—“

“Enough.” There was a hint of relief in Sherlock’s tone. “My god, I don’t need to hear about your sex life. Is that why you’re limping?“

“All right,” John said sharply, relief coursing through him. “None of your business, Sherlock. Let’s change the subject.” He attempted a smile. “What have you been up to?”

“I finished the tea that you abandoned, but otherwise nothing.” Sherlock sounded put out. “Nothing _remotely_ interesting.”

John had completely forgotten about the pot he’d abandoned before escaping…before. Casting his gaze on Sherlock’s throat, he tried to subtly check and see if there was any sort of marking, or anything that would let him know that he hadn’t been dreaming. He didn’t really know what he was hoping to find.

To his surprise, when Sherlock shifted and turned, John spied the same sharply colored mark against the highest point of his neck. His breathing sped up. “Quiet day, then?”

“Quite. Boring, yes. There’s nothing to _do!_ ”

For the next five minutes Sherlock lamented the fact that crime had recently seen a drop. John wanted to be annoyed by this, but this, _this_ was normal, and John would do just about anything for normalcy’s sake.

“Isn’t that a shame,” John said. He turned to make a new pot of tea for the two of them. “You could tell me what that fish tank is about. You filled it with water and it’s just been sitting there for a week now. Bloody thing is always in the way.”

“Hmm.”

When he glanced back, Sherlock was looking at it with a particular longing.

John prompted him again, but he wouldn’t elaborate as to its use. He was beginning to suspect something; as to any possible uses of a large tank, John wasn’t sure what to think.

With knowledge of Sherlock’s secret under his belt, John wasn’t sure of anything anymore.

He reminded himself to make sure that his gun was loaded, just in case.

That night, he had nightmares. Horrible ones that left his voice more hoarse than it had been in months. Monsters of all sorts chased after him in and around various parts of London, Afghanistan, and at home in Baker Street. Sometimes Sherlock commanded an army of them, grotesque tentacles bursting from his body, covered in blood and gore.

They never spoke of it. No matter how bad the nightmares were, Sherlock never said anything. John didn’t know if he paid enough attention to notice.

Life continued on, and more murders were committed. Eventually, the horror of what John had seen began to fade.

Underneath the fear, something even darker bloomed.

The dreams continued, but his dreams no longer depicted Sherlock as an evil overlord of gelatinous, bulbous monsters. Now he played a more active role.

_“How does it feel?” he whispered. Sherlock tugged at John’s cock with his fist, while three fingers pumped relentlessly in John’s arse._

_“Oh god,” he moaned. “Good, Sherlock. More.”_

_John’s exclamation was followed by a long moan into the crook of his arm. Squeezing underneath Sherlock’s fingers was a wet, slippery tentacle. He shuddered as it followed the path to his prostate and massaged the space firmly. John jerking violently in his constraints._

_Sherlock was watching his mate with rapt attention as John came apart under his careful hands. He writhed against the intrusion, but never rejected his advances. If anything he appeared to enjoy it thoroughly._

_Sherlock removed his fingers, but left the slick tendril writhing inside John's body. More of them circled him, holding John still with surprising strength. One entered his mouth, curling around his tongue and muffling his cries. John struggled only briefly before he let himself relax, floating on the sensation of being suspended. It was like like nothing he’d ever experienced. Tentacles wrapped around his cock, squeezing and sliding around the shaft. His shout was muffled as more tentacles surged into his open mouth._

_“Yes, John," Sherlock purred. "Very good. Do you know how I knew you would like this?”_

_John could barely manage to move his head in a weak nod. He felt ready to explode._

_“I heard you, that day. I knew you were there, watching.” He lowered his voice until it rasped, reverberating through John. “I wanted you to watch. And now_ I _get to watch.” With great effort Sherlock pulled back, and John felt extra pressure against his arse. Sherlock cock followed the path the tentacles had opened and thrust in next to the wriggling appendages inside. Overwhelmed, felt rather than heard himself scream._

_Oh—_

—fuck.

John woke up with his fingers in his mouth, and his fist around his cock. The dream replayed at the front of his mind, more vivid and real than any of his dreams previous. John released his prick as hot shame washed through him.

_What the hell is wrong with me?_

It had been easy to pretend that when the first time it happened, it was because of the adrenaline rush. Now the evidence was smeared across his pants. John got up and headed for the bathroom. He cleaned himself off, changed, and then slipped back under the duvet, shivering.

Before, it was easy to push aside dreams that were vague and faded with time, but this— there was no way in _hell_ that he would admit to wanting something like… _that_.

John did not sleep for a very long time.

* * *

The same dreams continued to plague John. They varied, but remained relatively similar; most depicted various situations in which Sherlock and he were either enemies or tangled lovers, although the latter was beginning to occur more often with alarming regularity.

John danced around what he knew of his best friend, alternating between accepting what he had seen—and what he now felt—and being repulsed. On most days John still struggled to look Sherlock in the eye; it wouldn’t have taken much for Sherlock to notice if he hadn’t been so preoccupied with his casework. John was just lucky that he had time, because sooner or later he was going to need to confront Sherlock.

It all came to head the night after a long case. Sherlock had been at the edge of his patience for weeks, something for which John was grateful. He paid him little heed, burying himself in the work. John did all but physically drag Sherlock in order to make him eat and drink.

John had taken a few days off from work because Sherlock had wanted his assistance with a case that led them to a remote location about an hour outside of London.

It wasn’t one of the more exciting ones, but dealing with bureaucracy was trying on both of them. As the case wore on, Sherlock started getting continually more snappish. He couldn’t sit still for more than a few minutes, and his attitude towards their clients grew particularly nasty.

John was forced to intervene when the first round of tears rolled down the client’s cheeks.

“Sherlock,” he hissed, pulling him aside, “what. The. _Hell_. Is your problem? Do you need me to remind you that _you_ were the one who insisted we take the case? Why are you acting like a child? We can’t help it that we have to go through a mess of red tape. _They_ can’t help it.”

Sherlock looked incandescent with frustration, fury lurking not far behind his eyes.

“He is _hiding_ something, John! Facts that could have speeded this process expediently if he wasn’t so bloody concerned with saving his own skin. If I had access to all of his files, this would have been finished hours ago. Fraud is _not my concern._ ”

“I understand,” said John slowly. “But we’ve dealt with this kind of situation before. What the hell makes this so different that you can’t behave yourself?”

“Everything, John! You may find dull pandering to be a part of your nature; I however, am trying to solve a _case_ —“

While John had little trouble meeting Sherlock’s stubborn nature head on, he found himself pressed against the nearby wall, bracketed by Sherlock’s inexplicable fury. When he realized the situation he was in—Sherlock did _not_ intimidate him, thank you—John pressed his palm flat against Sherlock’s chest and pushed him viciously in the opposite directly.

“Piss off,” John snapped. “You are not the only one who has to suffer when you get like this. Calm that big fucking intellect of yours and—“ John paused when he noticed something out of the ordinary. He hadn’t questioned Sherlock’s decision to wear his coat indoors, but now that he thought about it, it seemed so obvious.

“—and stop being such a dick,” he finished, trying not to stare. Peeking out on the flare of Sherlock’s coat was a single…. _tentacle_.

Sherlock was furiously saying something, but John was preoccupied. Suddenly everything snapped into focus. The recent addition of the tank, the long bathes, sending John out on errands that took hours, and giving how long they’d been away from Baker Street; it was hardly a surprise. It all made horrific sense. He was angry because his tentacles probably needed to keep moist. Right? Oh God, he didn't want to think about this right now.

“John?“

He snapped out of it, returning to his eyes to Sherlock's face. _Don’t look._ “No. Shut up, Sherlock.” John held up a hand. He aimed for a soothing tone and landed somewhere between frustration and fondness. “Look, just finish the case and we can go home, all right?”

“If it were that easy,” Sherlock hissed, “we’d already be in a cab headed back to London.”

“I get it, Sherlock. You’re angry. That doesn’t give you the right to act like such a child. Now get back in there and solve this case. Then we can go home and you can…relax.”

Sherlock’s face lost its angry hue and the look he was now giving John was inscrutable. After a moment’s pause, he straightened.

“Get him out of that room then. I need space to think,” Sherlock said calmly.

Then he swept past John, looking marginally less murderous. John followed him into the room and cajoled the client into following him into the hallway to have a chat about the case. He shot Sherlock a curious look every few minutes, disconcerted by the change in his attitude.

The return to Baker Street was quiet. Sherlock’s sudden silence made John anxious, shifting in his seat as he stared out the window. Since the incident where Sherlock lost control, John hadn’t seen another slipup, but Sherlock was shockingly composed. He even _apologized_ to the client, which was even more of a surprise.

“You all right?” said John quietly, turning to glance at Sherlock out of the corner of his eye.

Sherlock grunted.

“Look, I’m sorry if I made you angry, but you know that you were way out of line back there.”

“What?” Sherlock glanced at him. “No; I’m not angry. I’m thinking.”

“Ah.” John didn’t know what to say, curious but too exhausted to worry about what was bothering Sherlock. He’d likely find out tomorrow. “Usually you use me as a sounding board when you’re thinking.” He chuckled weakly, but it didn’t draw a response out of the detective. John coughed and looked back out the window.

Sherlock hummed.

Once they were finally back home, Sherlock made quick work of his coat, throwing it carelessly to his right. He then flopped onto the sofa in a graceless pile of limbs. “Finally,” he hissed. “Waste of time. Could have been doing things that are far more interested _._ ”

“Are you going to take a bath?” John prodded suddenly. He knew he shouldn’t mention anything, but he couldn’t help it. He was a little curious to know if he was right.

Sherlock head snapped up so rapidly that John almost took a step back. _Shit_. “It’s just…you seem more relaxed whenever you do that and I know the case was frustrating.”

Sherlock’s eyes never left his face. Suddenly he stood, approaching with a single-minded focus that both excited and terrified John.

John didn’t back up until Sherlock was inches from his face, feeling more awkward than afraid. “Erm, Sherlock?”

“You know,” he said simply.

“I know?“ John laughed weakly. “Know what?”

“About me. Don’t play stupid, John, it doesn’t suit you. You’re a very bad liar. Although you may be very unobservant in most matters, I am not.”

He bracketed John’s shoulders with his arms, trapping him. John could have escaped easily, but he was frozen. _He knows._

“Do not think I don’t notice where every part of my body lies every _second_ , however uncontrollable they may seem. Earlier you noticed something very...odd, didn’t you?”

John swallowed, avoiding eye contact. That was a mistake; when he looked down, he could see something undulating underneath Sherlock’s clothes. It surged underneath the tight fabric of his shirt, bulging grotesquely before slowly flattening. No— _elongating_. To his horror a single pink, fat tentacle emerged, wriggling curiously in the air before it continued its descent down Sherlock’s thigh.

“O-Oh, ” John whispered, his eyes wide as saucers. He finally met Sherlock’s eyes, expecting to see sadistic satisfaction. What he saw there surprised him; Sherlock looked _devastated_. In fact, he was doing his best to hide it. His expression wavered, caught between facing John’s reaction with defiance and anxiousness.

 _Oh_. It had never occurred to John that Sherlock might have a similar reaction to John’s; that he would be ashamed of his abnormality. It brought his world into sharp focus.

“So you know,” said Sherlock, and now John caught the note of resignation in his tone. “No wonder you’ve been avoiding me. Had I known, John, I would have told you you didn't have to worry if you wanted to leave—“

“Stop,” said John, surprising himself. When Sherlock made as if to withdraw, he did the only thing he could think of at the time and pulled him closer by the back of his neck. “I mean stop _thinking,_ you wanker.” It was Sherlock’s turn to look surprised.

“I know you think you’ve figured it out because you’re so bloody smart, but let me tell you.” He poked his chest. “Okay, yes. I know! I’ve known and I’ve been struggling with this for _weeks,_ Sherlock. Weeks! Because of your carelessness I’ve had time to come to terms with—with _this_ long before today.” He waved his hand in the general direction of the tentacle.

“Honestly, this is less weird than some of the things that I’ve come to expect from you,” he said. It wasn't a complete lie. “I think we can handle this like adults without either of us losing it, all right?”

“I…All right,” Sherlock said in a daze. “You—when did you first come to know about my…”

“Tentacles,” supplied John, taking vicious satisfaction in the way Sherlock’s cheeks pinked. He had the near irresistible urge to burst into giggles. “That day that you decided you were going to have a very weird wank with the door open, I came home early. Only I didn’t watch the telly like you thought; I saw you doing your thing and I got out of there as fast as possible.”

Sherlock’s complexion darkened further. _Serves him right,_ thought John.

“Yes, I remember. I thought you’d been with Sarah when in reality you—“ he stopped, closing his eyes as if he couldn't bear the sight of John. “John I’m sorry you had to see that.“

John held up a finger. “Don’t say you’re sorry. I was fucking terrified at the time, but I got over it.” Eventually. After a few dozen panic attacks. “And before you ask, no I’m not going to leave. I’ve stayed here for almost three years; I think I know what I can handle.”

It all seemed like too much for Sherlock to take in. He blinked at John like he was trying to reconcile everything he’d come to know with what John was telling him. John decided to give him a little help and do something that he had been thinking about for ages.

He reached for the tentacle and wrapped his fingers around the slippery surface. John was curious to know whether or not it had nerves, because it pulled back as if it was shy before suddenly pushing _up_ into his fingers. Sherlock gasped and shuddered, shoving his fist against his mouth before he realized what he was doing and let it drop to his side.

“John,” he rasped. “You’re not an idiot, so you know you shouldn’t touch whatever begs your curiosity. You have no idea what it does…” he trailed off as John’s fingers rubbed at the bulbous tip before sinking into the flesh. Sherlock jerked, his breath coming out faster.

“Don’t I?” John teased, letting the tentacle wrap around his wrist and pull him closer. “Is that you or is it actually acting on its own?”

“John!” Sherlock snapped. “If you don’t intend to stimulate me sexually then you need to stop. The… _tentacles_ ,” he sniffed, “work on a subconscious level, so they generally act upon my wants and desires.”

“And you want…” John trailed off. Sherlock did not meet his eyes, his face flushed all the way to the tips of his ears. Rather than feeling the same horror he expected to feel when face, John felt nothing more than arousal and a familiar fondness.

He _wanted_ this.

“Tell me if you want this.” John pulled his hand off of the tentacle. It was less, well, _wet_ than he’d been expecting, and he wondered if Sherlock was in need of that bath. “If you want this—and me—you need to tell me, because I want the same thing. But if I’m reading the situation wrong, then we can forget this ever happened.”

“What do you think?” Sherlock snapped. John raised an eyebrow, refusing to touch the tentacle that was pawing at his elbow until Sherlock made a choice. John noticed that more were peeking out from under Sherlock’s clothes, darkening the expensive fabric. “It doesn’t even have to be now. We do live together, so—“

“Oh, for god’s sake,“ Sherlock snarled, the gleam in his eye at odds with the words that came out of his mouth. John barely had time to take a breath before Sherlock’s mouth was on his and he’d been pushed against the wall.

John grunted, cupping Sherlock’s face to soften the kiss until it was a gentle press of lips. It came to no surprise that Sherlock was inexperienced; it was probably hard to find partners when you had more bundle of _issues_ that reaction to his subconscious.

Sherlock’s heart was beating rapidly against his chest and his eyes were clenched shut, but it was one of the most satisfying kisses of John’s life. Sherlock flinched when John’s tongue soothed the dry skin on his lower lip, but he pressed closer until John only had space to breathe. He tested the waters, slanting his mouth and deepening the kiss. Sherlock tensed, but his quiet moan made John suspect it wasn’t the bad sort of tension. John alternated between urging Sherlock closer for deep, sensual kisses, his tongue tracing over Sherlock’s teeth, and dragging his mouth down Sherlock’s neck and jaw, pressing wet, open mouthed kisses against the flushed skin.

“Sherlock,” he whispered, earning a muted groan. One hand gripped Sherlock by the back of his head while the other stroked the curve of his hip. Sherlock’s fingers clutched senselessly at his shirt and the tentacles had wrapped around John’s waist, pulling him closer with strength that he found dizzying.

“John,” Sherlock breathed, tilting his head for further exploration. He shuddered when John mouthed at the crook of his neck and almost forgot what he wanted to say. “You must know that I’ve never done this before.” He tried to sound unaffected but the sensations surrounding him made it difficult to think.

“I know,” said John. Tentacles wriggled underneath his shirt, warm and damp as they explored the hair skin of his stomach. “We can stop at any time, but if you’d like, I thought we could, um, take a bath.” It was his turn to blush.

“Yes,” Sherlock said, like there was nothing more that he wanted in the world. “I, they, desperately need one.”

With difficulty John extracted himself from Sherlock’s embrace. His tentacles, only a little bit slick now, didn’t want to let go and Sherlock had to focus very intently for a few moments before they retracted almost completely.

“That’s amazing,” John remarked once he could speak. “Is it okay if—may I see?”

Sherlock nodded. He unbuttoned his shirt with slightly shaking hands and let it fall to his elbows. John walked around Sherlock so he could look at what was going on. The tentacles, which had seemed so long, were now almost imperceptible nubs scattered along Sherlock’s back in no particular pattern or order.

It didn’t make any _sense_ , but he supposed that having tentacles in general wasn’t something that made for sense.

John removed the part of him that wanted to examine and learn about this phenomenon and wrapped his arms around Sherlock waist, pressing soft kisses along his shoulder blades.

“John.” Sherlock huffed. “If you don’t want a repeat performance we should get going. Control is very difficult for me right now.”

“Right.” John blushed and took Sherlock’s hands, feeling suddenly shy. Kissing him was one thing, but getting naked together—it all seemed so fast. “You’re sure you’re okay with this?”

“Of course,” he said breezily. John couldn’t sense that he was lying; although Sherlock was still deeply red, he seemed more at ease than John had ever seen him. “Come on, John.”

John made a noise that he would deny when Sherlock started shedding his clothing, leaving a trail to the loo. John followed him at a more sedate pace, leaving on his pants until he’d reached the precipice of the bathroom. Sherlock was stooped over the tub, long fingers fiddling with the knob until the water was at a temperature that he deemed acceptable.

“All good?” John approached and laid a hand on Sherlock’s lower back. The tentacles grew from his back and reached down to dip in the warm water.

Sherlock released a long sigh, the tension in his shoulders easing. John watched, incredibly curious as Sherlock stepped into the tub, the tentacles scooping up water before running themselves along the length of his chest and shoulders. Spreading it, he realized.

“Amazing,” John couldn’t help but say. Sherlock looked at him, his eyes gleaming.

“You are a marvel, John. Of all the people I thought I could share my secrets with, I never expected you.” He looked embarrassed at his own show of affection, but lifted his chin..

John didn’t know what to say to that. He felt the same. Was there any doubt? Instead of answering, he stepped out of his pants to join Sherlock in the half-filled tub, but not before giving him a quick kiss.

Immediately his arms were filled with a very excited detective. What Sherlock lacked in experience he made up for in enthusiasm, his mouth seeking John’s, now warm and moist. John had always admired the shape of his lips and took the opportunity to take the lower one between his teeth, biting down gently as his hands trailed up his back. Sherlock hummed and pulled John closer, his tentacles now exploring unrestrained.

There was something to be said about the extra wet layer. Now that they were soaked, the tentacles ran across his skin with new energy, shimmering with their own secretions that John would have to explore at a later date.

He shuddered as one brave tendril wrapped around his cock, half hard and quickly growing. “That must be useful,” John said, trying to sound unaffected and utterly failing.

“Mm.” Sherlock’s eyes were glazed as he watched the proceedings. It occurred to John that he was probably feeling a lot more from a variety of ends. He smirked, reached for the nearest tentacle, and took it between slippery hands. It writhed between his fingers, seeking sensation. John hesitated but for a moment before he put the end between his lips.

His arousal spiked at the feeling of it in his mouth. It was very different from his dreams; softer, yet unyielding. He closed his eyes and sucked, shivering when he was able taste the strange liquid it released. It was almost…sweet.

His pleasure was nothing compared to Sherlock’s. Various tendrils caressed his skin in a very practiced manner, undulating and wrapping around limbs sensually. Some circling his arms and thighs and squeezed, while other slid over his cock. Sherlock shuddered and jerked, his body at war with itself. John watched, rapt, one of the fat ones slid underneath the water and did something that made Sherlock moan loudly and arch.

“Sorry,” he hissed, clearly attempting to gain control. “I’ve never…your mouth. Fuck.” He shoved his fist in his mouth and bit down. “It’s different when it’s you. It’s—it’s always different when it’s you, John.”

Spurred on by his need to see Sherlock lose all of his control, John pushed the tentacle further into his mouth, doing his best to give Sherlock the approximate of a blowjob. By Sherlock’s reaction, whatever he was doing was working.

A few tentacles tentatively poked at the edges of his lips and John groaned, imagining himself stuffed until he choked. He felt ashamed that such thoughts permeated his mind, but a look at Sherlock assured him that he wasn’t the only one.

His pupils blown wide with lust, Sherlock watched the tentacle sliding out of John’s mouth with particular abandon. His mouth hung open and he gasped when the other tentacles tried to pry his mouth open with renewed effort. As much as he would have loved to explore that possibility, John pulled the one out of his mouth and swallowed what it left behind, feeling a little dizzy.

“Another time,” Sherlock said, almost to himself. John nodded and refocused. He didn’t even know where to begin. More tentacles had joined the one wrapped around his cock, sliding clumsily along the length. John felt about two seconds from exploding at this point, but he wanted Sherlock to come before he did. He wanted to _see_ him come apart without any distractions.

“You’re beautiful,” said John, pulling Sherlock clumsily into his lap. Sherlock straddled him with what space was available, tentacles waving lazily in the air. “Even more now that I’ve seen you like this.” He kissed his throat. “Gorgeous.”

“John. You’re…you’re more than I can— I can’t—“ John shushed him, realizing that some of his incoherence was caused by the tentacles that were fucking him relentlessly from behind. John had to concentrate on not finishing the night early at that image alone and wrapped his fist around Sherlock’s cock.

“Please,” Sherlock sobbed, his hips working uselessly.

“What do you want?” John kissed his chest, swatting the tentacle that was rubbing over Sherlock’s nipple so that he could pinch and flick it between his own fingers. Sherlock’s hips jerked wildly, and for a moment John thought Sherlock had come, but he realized that a slim tentacle was wrapped around the base, squeezing painfully.

Sherlock wavered, his mouth moving soundlessly before he bent his head to meet John in a searing kiss. John groaned as some of the tentacles played with his cock. One of them was doing a successful job of pulling down the foreskin, while another rubbed against the tip. The sensations were incredible.

“Fuck me,” Sherlock breathed against John’s lips. “I want to know what it feels like.“

John couldn’t really form words at the moment, but he was able to nod. The tub didn’t give him much room, but he’d make do. He’d make do with anything at this point. John pulled away and resituated himself, leaning against the outer edge of the tub. Water sloshed noisily onto the tile and he had the sense to turn off the running faucet before they made even more of a mess.

Sherlock fell into his lap, pressing himself flush against John’s hips. The tentacles thrust in deeply and he whimpered. “Now,” he said, grinding down impatiently.

“I— okay. Just hold on, love.” John deliberated against fucking him dry, but a look at the tentacles filling his arse eased John’s worries. Sherlock was _dripping_ with fluid, which turned on John more than he’d like to admit. As John held his cock with one hand while Sherlock hovered impatiently, he still hesitated. The tentacles made no move to remove themselves from Sherlock’s arse, and John wasn’t about to just force his way in, so he reached around to pull the tentacles out when suddenly, Sherlock released a long breath and sank down onto his cock.

“Oh god,” John exclaimed, his legs shifted aimlessly. His fingernails on his left hand dug crescents into Sherlock’s hip as he tried to make sense of what was happening. Fuck, that felt good. His arse was warm and slick and _tight_ , the tentacles already inside only adding to the sensation as they curled around his cock and _moved_.

“Oh god Sherlock.” He bit down on his knuckles, panting. “You feel so good. Holy shit.“

He wasn’t going to last more than a minute like this. He meant to warn Sherlock, but one look and he realized he needn’t have worried. Sherlock had barely managed to moved his hips before he made a choked off sound, clutching desperately at John’s shoulders.

There was so much to look for that John almost missed when Sherlock’s cock twitched and painted John’s stomach. John pumped Sherlock’s prick to draw out his pleasure, but he faltered when he noticed the tentacles; their reaction electric. They twitched and writhed, more erratic and forceful than John had ever seen them. He touched one of the fat tendrils and felt it go rigid under his fingers, and then relax before releasing that same fluid. The tentacles began to rub their fluid methodically all over Sherlock and John until they were shining.

“What are they doing?” John asked, his curiosity overtaking his own need. Sherlock shivered and rubbed his cheek against John’s shoulder, gathering enough of his wits to work himself on John’s cock.

“Shh. I want you to ejaculate first.” he lifted his head and kissed John, shifting until he could work John’s cock deeper. John choked, fingers grasping for Sherlock’s waist as he set a steady, if awkward pace that John did his best to match, lifting his hips until his muscles burned.

When more tentacles attempted to join the ones already stuffing Sherlock’s arse, John lost it. “God, Sherlock. _Yes_ ,” he hissed, holding Sherlock still as he fucked him roughly through his orgasm. Sherlock sighed and sagged against John, still twitching from the aftermath.

For a good minute, the two of them just focused on remembering to breathe. When John carefully pulled out, Sherlock’s eyes remained closed, his breathing deep and unsteady. He continued to shake long after John had recovered, which was frankly a little worrying.

“Hey,” John breathed, cupping his face between his hands. “Are you all right? Was all that too much for you?”

“Mm,” Sherlock trailed off. “Sensitive, John. Just sensitive. Imagine that every one of these appendages is a nerve that sends signals directly to the pleasure center of my brain.”

“Oh.” John had known that Sherlock felt pleasure, but he hadn’t really considered how intense that might make orgasms. “You’re all right though? I’m sorry if that was too much.”

“Don’t apologize. Ridiculous, John.” Sherlock concentrated and soon the tentacles were receding into his body. “I don’t usually orgasm for that reason, but I couldn’t resist when you looked so _interested_.” Sherlock opened his eyes and smirked.

John blushed. “Well! I’m. Glad. It was…enlightening.” He coughed. “Thank you for sharing that with me.”

Sherlock grinned. “Indeed. Now John, I would love to stay in this bathtub forever, but my legs are beginning to cramp. As a matter of fact, I’m not sure I can even move.”

“Fuck. Okay, right. Hold on.” After rinsing them off the worst of the mess with the showerhead, John stood on shaky legs and carefully climbed out of the tub. Most of the water had cascading onto the floor and they’d no doubt hear it from Mrs. Hudson by morning (that was going to be a fucking nightmare). He was mentally preparing his apology as he grabbed the nearest towel and helped Sherlock out of the tub. He moved like a newborn foal, leaning heavily on John until he was able to walk without swaying.

Sherlock flopped on his bed and John returned to the bathroom to grab a warm washcloth. He intended to clean off the strange sticky stuff from Sherlock’s tentacles, but when he rubbed the warm cloth over Sherlock’s bare shoulder, he noticed that it was no longer wet. He looked at his own skin; there were no traces and it didn’t feel sticky as he’d expected. “Huh. That’s weird. Is it supposed to just…disappear?”

Sherlock grunted. “I will explain it to you in full detail later. For now, I am exhausted. By morning I’m going to be _hungry_. Ugh.”

John grinned and sat down next to him. “Unfortunately, even the best of us have to eat. I’ll make your favorites.”

Sherlock opened one eye. “With syrup?”

John nodded solemnly. “Syrup. The bathroom needs cleaning before it makes things even worse, so I guess I’ll...” He wasn’t sure of his welcome and fidgeted. “…leave you be now. If you want.”

Sherlock’s hand landed on his thigh and squeezed. “Do not _guess_. If you can’t deduce I want you around post-coitus, you really are an idiot.”

John tried to frown at the insult but couldn’t quite manage less than a fond smile. “All right. Let me just put on some pants. You, too. Mrs. Hudson is going to rush up here in the morning and I for one don’t want to scar her.”

“Where’s the fun in that,” Sherlock chuckled as John left to fetch his clothing. Now alone he huffed and heaved himself off of the bed, stumbling over to his dresser. He put on pants and a shirt, just in case his tentacles decided to exercise during the night.

John stopped in the bathroom to set a layer of towels on the floor to soak up the worst of the mess. When he returned to Sherlock’s room, Sherlock was already snuggled under the covers. He released a shaky breath and climbed in behind him, his heart pounding wildly. He couldn't believe his luck.

John had barely settled when he heard a rhythmic pounding coming from below.

“SHERLOCK! WHAT HAVE YOU DONE TO MY FLOOR?”

 

**Author's Note:**

> Poor Mrs. Hudson.


End file.
